AA 4714 then DL 5704 at Boston
Harrisburg → Boston → Washington National
Timetable, Boston time
08:47AA 4714 from Harrisburg at the gate
21:45DL 5704 to Washington National leaves the gate
12 h 58 apart on the timetable
DL 5704 leaves 12 h 58 after AA 4714 arrives on the timetable: more than half a day, so not a connection we count.